½ cup extra-virgin olive oil, divided

5 pounds portobello mushroom caps, quartered, divided

1 ½ cups frozen pearl onions, thawed, divided

½ teaspoon table salt, divided

¼ teaspoon pepper, divided

⅓ cup all-purpose flour

4 cups chicken or vegetable broth

1 (750-ml) bottle red wine, divided (or 100% pomegranate juice or cranberry juice)

2 tablespoons unflavored gelatin

2 tablespoons tomato paste

1 tablespoon anchovy paste

2 onions, chopped coarse

2 carrots, peeled and chopped

1 garlic head, cloves separated (unpeeled), and smashed

1 ounce dried porcini mushrooms, rinsed

10 sprigs fresh parsley, plus 3 tablespoons minced

6 sprigs fresh thyme

2 bay leaves

½ teaspoon black peppercorns

1. Heat 3 tablespoons oil in Dutch oven over medium-high heat until

   shimmering. Add half of portobello mushrooms, half of pearl onions, ¼

   teaspoon salt, and ⅛ teaspoon pepper, cover, and cook, stirring occasionally,

   until mushrooms have released their moisture, 8 to 10 minutes. Uncover

   and continue to cook, stirring occasionally and scraping bottom of pot, until

   mushrooms are tender and pan is dry, 12 to 15 minutes. Transfer vegetables

   to bowl, cover, and set aside. Repeat with 3 tablespoons oil, remaining

   portobello mushrooms, remaining pearl onions, and remaining ¼ teaspoon

   salt and ⅛ teaspoon pepper.

2. Add remaining 2 tablespoons oil and flour to now-empty pot and whisk

   until no dry flour remains. Whisk in broth, 2 cups wine, gelatin, tomato

   paste, and anchovy paste until combined and no lumps remain, scraping up

   any browned bits. Stir in chopped onions, carrots, garlic, porcini mushrooms,

   parsley sprigs, thyme sprigs, bay leaves, and peppercorns. Bring to boil and

   cook, stirring occasionally, until liquid is slightly thickened and onions are

   translucent and softened, about 15 minutes.

3. Strain liquid through fine-mesh strainer set over large bowl, pressing on

solids to extract as much liquid as possible; discard solids. Return liquid

to now-empty pot and stir in remaining wine. Bring mixture to boil over

medium-high heat. Cook, stirring occasionally, until sauce has thickened to

consistency of heavy cream, 5 to 7 minutes. Reduce heat to medium-low, stir

in reserved portobello-onion mixture, and cook until just heated through, 3

to 5 minutes. Stir in minced parsley and serve.